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linux_gnu_awk_privilege_escalation.yml
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linux_gnu_awk_privilege_escalation.yml
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name: Linux GNU Awk Privilege Escalation
id: 0dcf43b9-50d8-42a6-acd9-d1c9201fe6ae
version: 1
date: '2022-08-09'
author: Gowthamaraj Rajendran, Splunk
status: production
type: Anomaly
description: gawk command in Linux is used for pattern scanning and processing language.
The awk command requires no compiling and allows the user to use variables, numeric
functions, string functions, and logical operators. It is a utility that enables
programmers to write tiny and effective programs in the form of statements that
define text patterns that are to be searched for, in a text document and the action
that is to be taken when a match is found within a line. If sudo right is given
to gawk tool for the user, then the user can run system commands as root and possibly
get a root shell.
data_source:
- Sysmon for Linux EventID 1
search: '| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time)
as lastTime from datamodel=Endpoint.Processes where Processes.process="*gawk*" AND
Processes.process="*BEGIN*{system*" AND Processes.process="*sudo*" by Processes.dest
Processes.user Processes.parent_process_name Processes.process_name Processes.process
Processes.process_id Processes.parent_process_id Processes.process_guid | `drop_dm_object_name(Processes)`
| `security_content_ctime(firstTime)` | `linux_gnu_awk_privilege_escalation_filter`'
how_to_implement: The detection is based on data that originates from Endpoint Detection
and Response (EDR) agents. These agents are designed to provide security-related
telemetry from the endpoints where the agent is installed. To implement this search,
you must ingest logs that contain the process GUID, process name, and parent process.
Additionally, you must ingest complete command-line executions. These logs must
be processed using the appropriate Splunk Technology Add-ons that are specific to
the EDR product. The logs must also be mapped to the `Processes` node of the `Endpoint`
data model. Use the Splunk Common Information Model (CIM) to normalize the field
names and speed up the data modeling process.
known_false_positives: False positives may be present, filter as needed.
references:
- https://gtfobins.github.io/gtfobins/gawk/
- https://www.geeksforgeeks.org/gawk-command-in-linux-with-examples/
tags:
analytic_story:
- Linux Privilege Escalation
- Linux Living Off The Land
asset_type: Endpoint
confidence: 50
impact: 60
message: An instance of $parent_process_name$ spawning $process_name$ was identified
on endpoint $dest$
mitre_attack_id:
- T1548.003
- T1548
observable:
- name: dest
type: Hostname
role:
- Victim
- name: parent_process_name
type: Process
role:
- Parent Process
- name: process_name
type: Process
role:
- Child Process
product:
- Splunk Enterprise
- Splunk Enterprise Security
- Splunk Cloud
required_fields:
- _time
- Processes.dest
- Processes.user
- Processes.parent_process_name
- Processes.process_name
- Processes.process
- Processes.process_id
- Processes.parent_process_id
risk_score: 30
security_domain: endpoint
tests:
- name: True Positive Test
attack_data:
- data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1548/gawk/sysmon_linux.log
source: Syslog:Linux-Sysmon/Operational
sourcetype: sysmon_linux
update_timestamp: true